The desiccation of



(No Model.)

J. W. HYATT, W. H. WO0D'& J..H., STEVENS.

EEooEss 01" AND APPARATUS OE EFFEGTING THE DESIGGATION 0E PYROXYLINE PULP. No. 296,968. A Patented Apr. 15, 1884.

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JOHN W. HYATT, WILLIAM H. WOOD, AND JOHN H. STEVENS, OF NEWARK, NEW JERSEY, ASSIGNORS TO THE OELLULOID MANUFACTURING COM- PANY, OF NEW YORK, N. Y.

PROCESS OF AND APPARATUS FOR EFFECTING THE DESICCATION F PYROXYLINE PULP.

SPECIFICATION forming part of Letters Patent No. 296,968, dated April 15, 1884.

Application filed February 11, 1884. (No model.)

To 42% whom it may concern.-

Be it known that we, JOHN W. HYATT, WILLIAM H. VVooD', and JOHN H. STEVENS, citizens of the United States, and residents of Newark, in the county of Essex and State of New Jersey, have invented certain new and useful Improved Processes and Apparatus for Effecting the Desiccation of Pyroxyline Pulp, of which the following is a specification.

to The invention has relation to an improved process and apparatus for effecting the desiccation of pyroxyline. WVe contemplate especially the treatment of pyroxyline pulp either before or after the pulp has been mixed with solvents, pigments, or other substances; but

it may be successfully employed in the treatment of pyroxyline which has not been reduced to the form of pulp.

The instrumentalities which we use in carrying out our process are a hydraulic press which isso constructed that enormous pressure can be produced, and metallic or other suitable sheets or pieces and pads or sheets of bibulous material, the sheets being adapted to the size of the press. The drawing shows a vertical section of such a press. 7

The pyroxyline is by preference made into the form of a cake or layer, and a pile erected or built up consisting of, first, a pad of bibulous material; second, a layer of pyroxyline; third, a pad of bibulous material; and, fourth, a metallic or other suitable sheet, the whole built up in this way to consist of as manylayers as may be convenient. The pile thus formed is subjected to enormous pressure, whereby the aqueous particles are expelled from the pyroxyline, suitable provision, being made for their escape, after which the pyroxyline is treated to remove any of the aqueous particles which may not have been expelled by the principal operation. The method in so far as it involves the use of sheets of bibulous material is not new, the use of bibulous sheets being described and claimed in Letters Patent of the United States No. 133,229, granted to 1. Smith Hyatt and John W. Hyatt for improvement in process of and apparatus for manufacturing pyroxyline, dated November 19, 187 2; but inthe said Hyatt process the water is extracted by absorption by means of dry blotting-papers under pressure, the operation being repeated several times by removing the wet papers and substituting dry ones until the cakesof pyroxyline are dry. The pressure used is about five hundred and 5 5 fifty pounds to the square inch of cake surface, and the water is entirely absorbed by the papers, which are afterward dried and reused. In our process the bibulous agents or blottingpapers are used in a different way, as hereinafter more fully explained.

\Ve are also aware that the employment of great pressure for the purpose of expelling the Water from wet pyroxyline is not new; but we have found that even where enormous pressure is used there are difficulties in effecting the permanent removal of the water that is expelled and preventing its being in part reabsorbed by the pyroxyline as soon as the pressure is discontinued. The object of our invention is to render the employment of great pressure by discarding or retaining control of the water as fast as it is expelled from the pyroxyline. This we accomplish by the use of bibulous material or blotting-pads in such a manner as to afford a ready escape for the water, and at the same time prevent the re turn of any considerable percentage to the cake of pyroxyline when the pressure is discontinued. Various bibulous substances such as sponge, cloth, linen, and felting-may be used; but we prefer to employ blotting-paper for many reasons. WVe do not find it necessary to renew them uiitil they are worn out; nor is it necessary that they be dried, because, although still containing considerable moisture after being subjected to the great pressure used in the operation, they retain sufficient capillary attraction to absorb whatever water may be present when the pressure is discontinued, thus preventing its return to the cake. By the use of our pads in connection with enormous pressure we are enabled to expel a large percentage of the water, leaving only about five per cent. to the weight of the 5 cake, which small amount is readily removed by a subsequent pressure between dry blotting-papers or otherwise.

In practice we prefer to grind the pyroxyline to a pulp by suitable means, at the same time mixing in camphor and such pigments or coloring materials as may be desired. As the pyroxyline in a dry condition is very inflammable, we prefer to leave about, say sixty per cent. of water in it, so that it can be mixed and ground without danger of ignition. After the grinding has been effected it is necessary to extract the moisture before the pyroxyline can be dissolved or converted into a solid compound, to effect which is the object of our in vention; but it is obvious, as hereinbefore' stated, that the pyroxyline can be deprived of its water by our process without grinding it or mixing it with camphor.

o take the pulp impregnated with water, as aforesaid, and form it into cakes of con venient thickness, and of a size adapted to the size of the press. Upon the platform A we place a metallic sheet, B, then a layer of bibulous material 0, formed of, say, a dozen sheets of blotting-papen then a cake of pulp, E, then a layer of bibulous material, C, then a metallic sheet, a layer of bibulous material, a cake of pulp, and so on, a pile of any desired height being formed in this way in which the layers of bibulous material are separated by metallic sheets and the cakes of pulp brought in contact with the bibulous surfaces, substantially as illustrated in the drawing; and for the purpose of preventing the bibulous surface from adhering to the cake of pulp a sheet of linen, :0, may be placed on each side between the paper and the pyroxyline cake or layer. After the pile has been formed, as hereinbefore set forth, pressure is applied, elevating the movable platform with immense power, causing the compression of the pile and the expulsion of the aqueous particles which are run off by means of the waste-pipe p or otherwise discarded. We have found that the thickness of the cake or layer of pyroxline, the thickness of the bibulous pad, the degree of pressure, and length of time the pressure is continued are considerations of controlling importance. For instance a cake of pulp twelve inches square ought to weigh after it has been desiccated say about thirty ounces, and each pad when formed for the same consisting, sayof a dozen sheets of blotting paper, should when dry weigh about twelve ounces. To accomplish the desiccation of the cake, the pressure used should be about seven thousand five hundred pounds to the square inch, and the pile of cakes should be left under pressure from forty to sixty minutes. To use a lighter or heavier cake or fewer sheets of blotting-paper would render the process less effective. In regard to the degree of pressure, to use less would not cause the removal of as large a percentage of water, and to use more would tend to wear out too rapidly the pads of bibulous material;

and where the continuance of the pressure is for a shorter time the percentage of water removed is considerably reduced. Under the conditions just stated the cakes of pulp retain say about five per cent. of water, which can be removed by one subsequent pressure in dry blotting-papers, or the final desiccation can be effected in a drying-room or otherwise, as may be convenient. \Ve prefer to use the blotting papers both for convenience and greater safety. However, where it has heretofore been the practice to dry the pyroxyline in quantities in warm air, the use of this process would leave so little moisture to be removed that the drying could be safely performed in fractional lots.

In using the term metallic sheets it is not to be understood that it is essential that the sheet shall be made of metal, as a sheet or plate of any material which will serve to divide the layers of bibulous material, and having sufiicient strength to resist the pressure and retain the shape of the pile may be successfully made use of.

WVhile the use of plates is desirable as enabling the treatment of a considerable number of cakes or charges of pyroxyline simultaneously, it is obvious that a single cake or charge may be-successfully desiccated by using only the bibulous or absorbing pads, the desiccation being as effectually accomplished as when the plates are used.

It is also obvious that the press which we have described is not in any sense of the essence of our invention, except as an illustration of a means whereby the process can be successfully carried out.

It will also be understood that different kinds of bibulous material may be employed, and that we do not limit ourselves to any particular kind.

e strongly recommend the use of blottingpaper, the advantages of which have been referred to; but we do not limit our claim to the use of any particular kind of bibulous material, nor to bibulous material in any particular condition.

\Vhat we claim as our invention, and desire to secure by Letters Patent, is

1. The process herein described of effecting the desiccation of pyroxyline containing water, which consists in, first, subjecting it, with an absorbing agent, to great pressure in a press, whereby a large percentage of the aqueous particles are expelled; and, second, removing the moisture that remains by subsequent treatment of an analogous character or otherwise, substantially as set forth.

2. The process of effecting the desiccation of pyroxyline pulp containing water herein described, which consists in, first, forming the pulp into a cake; second, subjecting the cake to great pressure in contact with a surface of bibulous material, whereby a large percentage of the aqueous particles is removed; and, third, completing the desiccation by subjecting the partly-desiccated material to the action of a surface of dried bibulous material or otherwise, substantially as set forth.

3. The process herein described of effecting the desiccation of pyroxyline containing water, which consists in forming a pile composed of a series of layers of pyroxyline, bibulous material, and plates B, and subjecting the pile thus formed to pressure, substantially as set forth.

4. The process herein described of effecting the desiccation of pyroxyline containing water, which consists in forming a pile composed of a series of layers of pyroxyline, bibulous material, and plate B, and subjecting the pile thus formed to pressure, and then subjecting the pyroxyline to further treating the pile thus formed to pressure, substantially as set forth.

6. The process herein described of effecting the desiccation of pyroxyline containing water, which consists in forming a pile composed of a series of layers of pyroxyline, blotting-paper, and plate B, and subjecting the pile thus formed to pressure, and then subjecting the pyroxyline to further treatment by means of dry bibulous material, or otherwise, to free it from the moisture which remains, substantially as set forth.

7. The process herein described of effecting the desiccation of pyroXyline, which consists in, first, subjecting it with an absorbing agent to great pressure in a press, the pressure being continued for a given time; and, second, effecting the removal of the moisture which remains by subsequent treatment with JOHN W. HYATT. \VILLIAM H. WVOOD. JOHN H. STEVENS.

Vitnesses:

CHAS. G. GILL, HERMAN Gus'row. 

